package com.lagou.edu.filter;

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpCookie;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.nio.charset.StandardCharsets;
import java.util.regex.Pattern;

/**
 * token验证，只拦截/api/user/info请求
 */
@Component  // 让容器扫描到，等同于注册了
@Slf4j
public class TokenFilter implements GlobalFilter, Ordered {

    /**
     * 过滤器核心方法
     * @param exchange 封装了request和response对象的上下文
     * @param chain 网关过滤器链（包含全局过滤器和单路由过滤器）
     * @return
     */
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        ServerHttpResponse response = exchange.getResponse();

        String path = request.getURI().getPath();

        HttpCookie tokenCookie = request.getCookies().getFirst("token");
        if(Pattern.matches("/api/user/info/\\S*", path)  && tokenCookie == null) {
            log.error("还未登录，拒绝访问");
            // 拒绝访问，返回
            response.setStatusCode(HttpStatus.UNAUTHORIZED); // 状态码
            String data = "你还未登录，请先登录";
            DataBuffer wrap = response.bufferFactory().wrap(data.getBytes(StandardCharsets.UTF_8));
            return response.writeWith(Mono.just(wrap));
        }

        // 合法请求，放行，执行后续的过滤器
        return chain.filter(exchange);
    }


    /**
     * 返回值表示当前过滤器的顺序(优先级)，数值越小，优先级越高
     * @return
     */
    @Override
    public int getOrder() {
        return 0;
    }
}